Mitt Romney portrayed himself today as a sober, seasoned alternative to Newt Gingrich in the Republican race for president.

The former Massachusetts governor suggested to the Des Moines Register editorial board that he has had more experience leading organizations than the former U.S. House speaker has had.

When asked to compare himself to Gingrich, Romney said: “Tell me about the person’s capacity to lead. Has the person been a leader before, and how do they lead? What kind of job did they do? What did the people around them think about that job? What is the enterprise that they led? How did it do under their leadership?”

He noted that he has led two successful businesses, an Olympics and the state of Massachusetts. He noted that most of his career has been spent in the private sector. “Speaker Gingrich has spent the last 30, 40 years in Washington. Nothing wrong with that. It’s just different.”

“I respect the speaker as a very bright and capable guy, but we’re very different people,” Romney said. “…We’ve followed very different paths. And I happen to think that at a time like this, someone who has spent their career in the private sector, and who has led time and time again in the private sector, and also in the governmental sector, has by far the best chance of defeating the president and fixing the country.”

Romney suggested that some of Gingrich’s ideas are offbeat. He alluded to a statement Gingrich recently made in which he said children in inner-city schools should do janitorial work. “I disagree with the speaker that we should eliminate some parts of the child labor laws so that kids can clean schools,” Romney said. “I don’t think that’s a great idea.”

Romney added that he’d read that Gingrich had suggested putting a permanent colony on the moon and using mirrors in space to light highways on Earth. “I think we’ve got some other priorities for our spending,” he said.

Gingrich, whose campaign cratered last summer, has surged to the front of the pack in recent weeks. But Romney indicated he’s not concerned.

“My guess is that over time, Speaker Gingrich will follow a trajectory that will be unique to him but that will come down, and by the time we’ll finish with this, I’ll get the nomination,” he said. “If I didn’t think that, I wouldn’t be battling like I am. I expect to get the nomination. It’s not a sure thing and I face tough competition but I’m pretty pleased with the fact that I’ve been either at or near the top of the polls in most states for a long period of time.”